C-C Bond Formation via Direct Functionalization of Indolizines with a Bichromophoric Ruthenium Photocatalyst

An unprecedented photocatalyzed radical C-(sp²)-C-(sp³) alkylation protocol to prepare a range of substituted 3-alkylated indolizine derivatives, mediated by 2-mercaptothiazolidinium salts as radical sources and a new dyad-like Ruthenium complex as a photoredox catalyst, under green light irradiation, resulted in yields of up to 99%. The mild, robust, and chemoselective procedure employs inexpensive, air-insensitive, and readily accessible reagents, enabling convenient synthesis of the substituted indolizines. Moreover, different N-heteroarenes, such as 1H-indoles and 2H-indazoles, were successfully alkylated under the optimized conditions. The resulting alkylated products are scaffolds with significance for drug design in medicinal chemistry.